Process of treating natural cellulose textiles to partially esterify them and then treating with a resin condensation product and products resulting therefrom



V Patented July 21,1953 2,646,340

- i QFFILCE it enem V ruocrrss er TREKTING'INK'EURAL ennui:

' Losn'raxtrrnasuo PARTI'Z'ALLYEST RIFY THEM *AND THEN TREATINQ WITH 3 I RESIN coNDENsATwN rnonuo r- 7 -rnoouorsRusULTING THERE Ro Ralph; E. :Ni c'kerson;Marblehead,Illllassglassignor to.Monsanto Chemical CompanyfSLTLouis, Mo

l'a corporation of Delaware 1 No Drawing. fA'pplication October 1 194a,

;Serial.No. 525399 t r 11 This invention relates to improvements in the manufacture .oi crush :and wrinkle l resistant textile.materials :and particularlynatural cellulosic teatile materials.

t lt has been possible; heretofore to -treatv-natural eellulosic atextile smaterials :such as cotton and U i g with the accessible hydroxyl groups t'of Ithe cellulose niicllae or molecules undersuchlcon linen textiles with turea-aldehydeandmelaminealdehyde condensation products and thereby e1- ter the physicalcharacteristics of the textile materialsafiterthelcondensation product wasinsolubilized thereon. hen l-relatively small amounts of suoh condensation products 4- are deposited on theznaturalcellulosic textilegmaterials, it is possible-to rprepare ra textile, product having a fair degree of idimensionalestability against washing,

that is, ithe Jtextile product is relatively resistant to shrinkage ".On laundering. When-relatively large-amountsofesuchtcondensation products are v deposited on -a natural =cellulosic textile product,

it l-i-s not only possibletorachievea higher degree of dimensional =stability,"-but *it is also p'ossible to produce a vtextile product :having resistance to crushing or wrinkling, that :is, the textile. product is adapted .-to :return -to its normal configuration or dimension after being creased or crushed. However, tex-tilemroductsof "the latter type, especially, .:have certain .disadvantages which have beeniobj'ectionable to "the trade with the result that they :have not been accepted commercially on .alarge scale. Such textile products areobjectionable =because they :are wembrittled and undergoxexcessive loss in tensile :streng-th as :a result of theltreatr'nen-t with the above described :con- 'densation products. These disadvantages be come :more apparent as the amount of condensation product depositedbn the textile material isv'increased.

Itis-one-objectofthe present invention to provide-a method of improving the dimensional stability and particularly 'the crush and/or wrinkle di-tions that only afpartial esteri fic'ation or e'therification of the cellulose' is effected and 'the'ce l lulosel-is not swollen to an appreciablyv greater -extentihan it Would b esw'ollenin wateralone; .Tliis ire-treatment Lis preferably carried out with an organic lesterifying agent and more particularly with formiclacid.

' The resulting product islreadilydistinguished from textile materials which lhave been highly esterified .or-etheri'fied or whichfhavebeenlspun from solutionslo'f cellulose esters .or thersiinithat the Zfirst mentione'd rnaterial swells readily in water "inwmuch the same manner as unmodified cellulose or "regenerated cellulose while the latter =typevof materials are quite resistant Ito. swellingin water-and aresoluble in certain organic condensation :products.

solvents :which do not appreciablyvaffect unmodified or regenerated (cellulose or the aforementioned lpartially resteri fied or etherified cellulosic materials. I After the cllulosic textile materials havebeen above arev preferred for the purposes of the presresistance of natural lcellulosic textile materials Without appreciablyaembrittling and lowering the tensile.strengthofsuch materials. v y g 1 A further olojec't of :the present invention is to ,provide icru'shiand/or wrinkle resistant natural cellulosic textile materials which are char acterized by -.excellent dimensional stability r and goodfieiibilityandtensile-strength. 7

Still .Ifurther objects and advantages Of the presentiinven'tion ,will appear from the following descrip'tionan'dtheappended. claims.

In accordance fwithetherpresent invention iacellulosic .textile,material such as cotton, linen, rainic and the like .is -first t given a 1pre-treatment with an organic agent which is capable of reactent invention. The amount of condensation product'deposi'ted on the cellulosic material may be varied to va .considerableextent depending on the :particular cellulosic textile which is being treated. .Bestresults have been obtained by 'deposit'ing from about 6 tol'6 by weight condensation product, "based on the textile, on:natural i celluloses suchas cottons vandilinens.

iI'he \cellulosic ltextile, after it has been im- Pregna'ted with the above described condensationproduc't orlproduc'tsg is LthenIheat-treated to cure vor linsolubilize the condensation ,produot or resin, that is, the condensation product is :rendere'd .waterlres'istant by converting it, through polymerization ;or-.condensation, to its infusible form. This is accomplished by :heating the impregnated textile, preferably after tit :has been dried, to :a temperature -.of from about 275 fto 350.4F. 'for-a period of iron 1 30 to 2-minutes de-,

condensation product before the impregnation' of the cellulosic textile material. It is preferable to give the finished textilematerials'saneutrah izing wash in a dilute alkaline solutionafter the heat treatment referred to above in order tO remove the major portion cf catalyst from the'textile. The finished textile product possesses a high degree of crease and wrinkle resistance and has a tensile strength which is substantiallythe same as the untreated material from which it is textilemay be excessively tendered when it is prepared.

4 ing agents of the invention by employing an excess of the esterifying agent. This may be accomplished, for example, by employing from 25 to 50 parts of esterifyirig agentfor, I parser cellulosic textile. Relatively low esterification temperatures are also preferred since it thus is easier to avoid excessive .esterification of the cellulosic materials. Temperatures of from about to 35 C. have been found to be very satisfactory for this purpose.

After the esterification treatment is completed, it is essential to wash out unreacted esterifying or'etherifying agent from the cellulose textile prior to the treatment with urea or melamine- In carrying out the pre-treatment of the cellu-i losic textile as described above, almostany orstable product with cellulose may be employed, Itis believed that by replacing the hydrogen of the cellulose hydroxyl groups with such agents the cross-linking of the cellulose molecules by the urea-aldehyde or melamine-aldehyde condensation product or other condensation product is substantially prevented. Therefore, the Cel1u' losic textile is not appreciably embrittled and does not appreciably lose its tensile strength as a result of the treatment. However,'it is not intended that the present invention be limited by any theory presented herein. Formic acid, as previously pointed out, is the preferred organic hydrogen-replacing agent for use in the pretreatment of cellulose because it"is easier to control the esterification and a superior product is produced after resin treatment. However, other esterifying agents such'as acetic acid, acetic'anhydride, propionic acid and propionic anhydride may also be used instead of formic acid, if an esterifying catalyst is employed. Etherifying agents such as dimethyl and diethyl sulfate may be used in place of esterifying agents, if the cellulose has been prepared to react with such agents, for example, by pre-treating the cellulose with caustic soda. When formic acid in concentrations of 85 to 100% by weight is employed, satisfactory results are obtained by'treating the cellulosic textile for 30 minutes at 60 C. or for 16 hours at 20 C. Formic acid in concentrations of less than about 80% by weight is not an effective esterifying agent without strong esterifying catalysts which are undesirable. Other esterifying-conditions may also be employed. However,

it is not desirable to carry'the-sterification or etherification reaction too far as the physical properties of the textile may be adversely affected.

It has presently been found that an esterification of at least 1% and not more than 10% of the available hydroxyl groups of the cellulose yields a very satisfactory product when further treated with a urea-formaldehyde or melamine-formaldehyde condensation product. The degree of esterification can readily be determined by taking aldehyde condensation product, otherwise the heat-treated to cure or insolubilize the condensation product. This may be followed by drying prior to resin treatment for ease in handling, but the drying step is not essential.

' The partially esterified cellulosic textile may be impregnated witha urea-aldehyde or melamine-aldehyde condensation product in-avariety of ways as, for example, by padding the textile through an aqueous solution-of the condensation product, by immersing the textile in the aqueous solution of condensation product and then centrifuging the textile to remove excess solution or by'spraying the aqueous solution of condensation producton the'textile. The concentration of condensation product in the aqueous solution is preferably such'as will deposit the quantity of condensation product as hereinbefore described depending upon the impregnation method employed. Generally-an aqueous solution having a concentration of condensation product of from 6 to 20% by weight is suitable for the treatment of partially e'sterified or etherified natural celluloses such as cotton and linen. The aqueous impregnating solution preferably comprises about 0.2 to 0.4% by weight of a latent curing catalyst for the condensation product and may also comprise other additives such as penetrants, softening agents and the like. A small amount, say about 0.5 to 2% by weight of a penetrant such as anionic and nonionic wetting agents aids the penetration of the condensation product into the textile fibers especially if the fibers are slightly oily or greasy. Sodium salts of alkylated benzene sulfonic'acids havin a long alkyl chain and polyethylene glycol derivatives of alkylated phenols having. a long alkyl chain are respective exam les of an anionic and nonionic wetting agent.

The urea or melamine-aldehyde condensation products employed inthe present invention are substantially unpolymerized or are substantially uncondensed, that is, they are essentially monomeric or only slightly polymerized when applied to the cellulosic textile. The condensation products of urea or melamine with'formaldehyde or mixtures thereof are particularly useful for the purposes of the present invention and are preferred over other condensation products prepared from other amines and adehydes. However, alkylated urea-aldehyde condensation products and alkylated melamine-aldehyde condensation products and particularly the methylated urea formaldehyde or melamine-formaldehyde condensation products or mixtures of the above described condensation products may also be employed, although they are not as desirable as the ureaformaldehyde or melamine-formaldehyde condensation products for producing crush resistance.

The aqueous solutions: of urea or melaminealdehyde condensation products employed herein may be prepared according to the known methods-of the prior art. A suitablemethod for preparing aqueous solutions of substantially unpolymerized-condensation products from urea and formaldehyde-is to react urea-with a neutral aqueous formaldehyde solution under refluxing conditions and in a mildly alkaline solution, that is, a solution having a pH of about '7.5'to.9 until the urea dissolves, after which, the solution is cooled and diluted to the desired'concentration. Aqueous solutions containinga melamine-formaldehyde condensation product are suitably; prepared by reacting melamine and an aqueous solution of neutralized formaldehyde under. refluxing conditions and in analkaline solution until solution of' the melamine occurs} after which, the solutionis cooled and diluted to -the desired concentration. Alkylated derivatives of urea or melamine-aldehyde condensation product are prepared satisfactorily by further reacting the above condensation products at temperatures of from 60 to 100 C. with a monohydric alcohol having from 1 to 3 carbon atoms such as methanol, ethanol and the like or with a dihydric alcohol having from 2 to 6 carbon atoms such as ethylene glycol, diethylene glycol-andthe like. ;Thereaction with monohydric ordihydric alcoholis preferably carried out under acid conditions by adjusting the acidity. of the original condensation product and the alcohol below about pH 3 usin a mineral acid such as hydrochloric acid, phosphoric acid and the like.

In carrying out the condensation of urea or melamine with an aldehyde, formaldehyde is preferably employed: as the aldehyde since the condensation product prepared therefrom possesses better water solubility than'condensation' products prepared from other aldehydes. However, aldehydes such as acetaldehyde, 'glyoxal,

furfural, propion aldehyde and the like may also be employed. In addition, products such'as paraformaldehyde which yield formaldehyde under the conditions of reaction may also'be used in-' stead of formaldehyde. I

A further understanding of the invention will" be obtained from the followingexamples which are intended to be illustrative, but not limitative of the'present invention, parts and percentages being by weight unless otherwise specified.

Example I An aqueous solution 7 of melamine-formaldehyde condensation product (hereinafter referred to as resin solution A) was prepared as follows:

One mol'of melamine was reacted with 4=mols of formaldehyde in the form of a 37% aqueous solution ata temperature of 180 C. using a'reflux condenserand at a pH of about 9 (glass electrode) The pH was adjusted to the above value by the addition of a 25% aqueous solution of caustic soda. The mixture was heated at a'tem- 'perature of 80 C. for a period of 5 minutesby 'which time solution of the melaminehad occurred. The solution was then cooled to room The solution contained about 54% of substantially unpolymerized or monomeric melamineformaldehyde condensation product.-

A linen fabric was pro-treated for about 16 hours and at room temperature in an 85% solution of formic acid. Approximately 30 parts of 85% formic acid were employed for l part'of linen fabric. After this treatment excess formic 6 acid was removedby extracting the fabric in a centrifuge and the unreactediacid still re? maining in the fabric was then removed by wash-. ing the fabric with cold water. The fabric was V air-dried after the washing step. i

The above air-dried fabric was padded through an aqueous solution prepared by diluting resin 7 solution A (prepared as described above) until it contained 16% resin solids. The solutionalso contained about.0.3.% of .2- amino-2-methy1 prov panol phosphate as a c atalyst and 1% of sodium.

dodecyl benzene sulfonate as a penetrant. The pad pick-up was adjusted so that .the fabric would pick .up a weight of solution equal'to 75% ofthe dry fabric weight (12% condensation product being thereby deposited on the fabric).

The fabric was then-framed, dried for 5 minutes at 180 F. and cured for 5 minutes at 300 F.- Finally, the fabric was given a neutralization. wash in a very dilute soap solution containime: 0.25% sodium carbonate, rinsedand then dried.

A linenfabric, which had notbeen pre-heated: I

a with formic acid, was treated with melamine! -on-merebending.

The following table indicates the relative temperature and employed as described below.

formaldehyde condensation product substanr tially in the same manner as set forth immediately above. After curing, this fabric ruptured wrinkle resistance, strength and stiffness 'of.un'-, treated andthe above treated linenfabricsz' ,A cotton fabric was pre-treated for 16- hours at room temperature in a formic acid solution using about 30 parts of 90% formic acid solution to 1 part of cotton fabric. Unreacted formic acid was washed out of the fabric with water and the fabric was then padded through an aqueous solution of melamine-formaldehyde resin prepared by diluting resin solution A .(prepared as described in Example I) until. it contained about 15% condensation product. The

solution also containedabout 0.25% I of zinc chloride'as a catalyst and about 0.15% ofithe reaction product of 10 mole of ethyleneoxide and 1 mol of dodecyl phenol as a penetrant- The pad pick-up was adjusted so as'to deposit about 11.6% of condensation product on the dry fabric weight. The resin treated fabric wasdried for 10 minutes at 200 F. and then curedat 310" F.

for 4 minutes. Finally, the fabric was given a neutralizing wash with 0.01% soap solution containing about 0.6% soda ash and then dried.

A cotton fabric treated in the manner de-.

' scribed has good wrinkle and crease resistance, is

quite flexible and soft and its tensilestrength-is not appreciably lowered as a result of the treat ment, thatis, it has substantially the same ten-.-

sile strength as an untreated cotton fabric. rrom.

the same roll.-

7 then cured for 4 minutes at 315 1''.

Example III A linen fabric was pre-treated with formic acid as described in Example I, washed to remove unreacted acid and then air dried. The partially formylated fabric was then padded through an aqueous solution of urea-formaldehyde condensation product which solution was prepared by reacting about 1 mol of urea with about 1.5 mols of formaldehyde, adjusting to pH of 8.5 by the addition of caustic soda under refluxing condi tions for approximately '7 minutes and then cooling and diluting the resulting solution until it contained about 16% resin solids. The impregnating solution also contained about 0.3% diammonium hydrogen phosphate as a catalyst and about 0.1% of sodium stearyl benzene sulfonate as a penetrant. The pad pick-up was adjusted soas to pick up about 13% condensation product based on the dry fabric weight. The fabric was framed, dried at 180 F. for about minutes and Finally, the fabric Was given a neutralizing wash in a 0.025% oap solution containing about 0.25% soda ash and then dried.

A linen fabric from the same roll was treated with urea-formaldehyd condensation product in substantially the same manner, but the fabric Was not treated with formic acid prior to the resin treatment. r

The relative wrinkle resistance, stiffness and strength of the untreated and the above treated linen fabrics compared quite closely withthe corresponding fabrics treated as described in Example I.

The curing catalysts described in the foregoing examples may be replaced with other curing catalysts depending upon the particular condensation product employed. For example, latent curing catalysts such as ammonium chloride, diammonium hydrogen phosphate, zinc chloride, ethanol amine hydrochloride and 2-amino-2- methyl propanol hydrochloride are employable with urea-formaldehyde condensation products. Latent curing catalysts such as zinc chloride, 2- amino-2-methyl propanol hydrochloride or phosphate and ethanol amine hydrochloride and phosphate are suitable for curing melamineformaldehyde condensation products in the presence of heat. Strong latent curing catalysts such as ammonium chloride, diammonium hydrogen phosphate, mineral acids and the like should not be employed with monomeric melamine-formaldehyde condensation products, however, since premature polymerization of the resin occurs before thorough'impregnation of the textile materials and the resulting product has a harsher and stiffer hand than is desirable.

The present invention may be practiced or carried out on loose fibers, unwoven yarns or filaments and other forms of textile materials in addition to fabrics. Union fabrics containing natural cellulosic yarns or mixtures of natural and regenerated cellulose yarns with wool or other protein yarns, cellulose derivative yarns and the like may also be treated in accordance with the present invention.

What is claimed is:

1. The method of preparing improved wrinkle or crease resistant cellulosic textile materials which comprises treating a natural cellulose tex- V tile material with an 80 to 100% formic acid soluaqueous solution comprising a latent curing catalyst and from about 6 to 20% by weight of a substantially unpolymerized ureaformaldehyde condensation product; extracting said material to deposit from about 6 to 16% by weight, based on the dry material, of said condensation product; and then insolubilizing said condensation product by heating said material at a temperature between about 275 and 350 F.

2.,The method according to claim 1, but further characterized in that a substantially unpolymerized, melamine-formaldehyde condensation product is employed instead of a urea-formaldehyde condensation product.

3'. The method of preparing an improved wrinkle or crush resistant cellulosic textile material which comprises reacting a natural cellulose textile material with an organic esterifying agent selected from the group consisting of formic acid,acetic acid, acetic anhydride, propionic acid and propionic anhydride until from 1 to 10% of the hydroxyl groups of the cellulose have been reacted with said agent; removing substantially all of the unreacted agent from said material; impregnating the resulting material with an aqueous solution comprising a latent curing catalyst and from about 6 to 20% by weight of a substantially unpolymerized condensation product selected from the group consisting of urea-formaldehyde, melamine-formaldehyde, methylated urea-formaldehyde and methylated melamine-formaldeh de condensation products and mixtures thereof; extracting said material to deposit from about 6 to 16% by weight, based on the dry material, of said condensation product; and then insolubilizing said condensation product by heating said material at a temperature between about 275 and 350 F. a

4. The method of preparing improved wrinkle or crease resistant cellulosic textile materials which comprises treating a natural cellulose textile material with a solution containing from to by weight of formic acid until from 1 to 10% of the hydroxyl groups of the cellulose are esterified; removing substantially all of the unreacted formic acid from said material; impregnating said material with an aqueous solution comprising a latent curing catalyst and from about 6 to 20% by weight of a substantially unpolymerized condensation product selected from the group consisting of urea-formaldehyde, melamine-formaldehyde, methylated urea-formaldehyde and methylated melamine-formaldehyde condensation products and mixtures thereof; extracting said material to deposit from about 6 to 16% by weight, based on the dry material, of said condensation product; and then insolubilizing said condensation product by heating said material at ,a temperature between about 275 and 350 F.

5. A wrinkle and crease resistant cellulosic textile material consisting of partially esterified natural cellulose textile fibers selected from the group consisting of partial formyl, partial acetyl and partial propionyl esters of natural cellulose,

in which from 1 to 10% of the hydroxyl groups of the natural cellulose have been esterified, impregnated with from about 6 to 16% by weight, based on the dry material, of an insolubilized condensation product selected from the group consisting of urea-formaldehyde, melamine-formaldehyde, methylated urea-formaidehyde and methylated melamine-formaldehyde condensation products and mixtures thereof, said fibers being characterized by a tensile strength which is substantially the same as the untreated natural cellulose textile fibers from which they were prepared. V l

6. A wrinkle and crease resistant cellulosic textile material consisting of partially formylated natural cellulose textile fibers, in which from 1 to 10% of the cellulose hydroxyl groups have been formylated, impregnated with from about 6 to 16% by weight, based on the dry material, of an insolubilized urea-formaldehyde condensation product, said fibers being characterized by a tensile strength which is substantially the same as the untreated cellulosic textile fibers from which they were prepared.-

'7. A wrinkle and crease resistant cellulosic textile material consisting of partially formylated nativecellulose textile fibers, in which from 1 to 10% of the cellulose hydroxylgroups have been formylated, impregnated with from about 6 to 16% by weight, based on the dry material, of an insolubilized melamine-formaldehyde condensation product, said fibers being characterized by a a tensile strength which is substantially the same as the untreated cellulosic textile fibers from which they were prepared.

8. A wrinkle and crease resistant cellulosic textile material consisting of partially formylated natural cellulose textile fibers, in which from 1 to Number 10% of the cellulose hydroxyl groups have been formylated, impregnated with from about 6 to 16% by weight, based on the dry material, of an insolubilized condensation product selected from thegroup consisting of urea-formaldehyde,

fmelamine-formaldehyde, methylated urea-formaldehyde and methylated melamine-formaldehyde condensation products and mixtures thereof, said fibers being characterized by a tensile strength which is substantially the same as the untreated cellulosic textile fibers from which they were prepared.

. RALPH F. NICKERSON.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Chemical Abstracts, 1944, Volume 38, 1883(5). 

1. THE METHOD OF PREPARING IMPROVED WRINKLE OR CREASE RESISTANT CELLULOSIC TEXTILE MATERIALS WHICH COMPRISES TREATING A NATURAL CELLULOSE TEXTILE MATERIAL WITH AN 80 TO 100% FORMIC ACID SOLUTION UNTIL FROM 1 TO 10% OF THE HYDROXYL GROUPS OF THE CELLULOSE ARE ESTERFIED; REMOVING SUBSTANTIALLY ALL OF THE UNREACTED FORMIC ACID FROM SAID MATERIAL; IMPREGNATING SAID MATERIAL WITH AN AQUEOUS SOLUTION COMPRISING A LATENT CURING CATALYST AND FROM ABOUT 6 TO 20% BY WEIGHT OF A SUBSTANTIALLY UNPOLYMERIZED UREAFORMALDEHYDE CONDENSATION PRODUCT; EXTRACTING SAID MATERIAL TO DEPOSIT FROM ABOUT 6 TO 16% BY WEIGHT, BASED ON THE DRY MATERIAL, OF SAID CONDENSATION PRODUCT; AND THEN INSOLUBILIZING SAID CONDENSATION PRODUCT BY HEATING SAID MATERIAL AT A TEMPERATURE BETWEEN ABOUT 275 AND 350* F.
 5. A WRINKLE AND CREASE RESISTANT CELLULOSIC TEXTILE MATERIAL CONSISTING OF PARTIALLY ESTERIFIED NATURAL CELLULOSE TEXTILE FIBERS SELECTED FROM THE GROUP CONSISTING OF PARTIAL FORMYL, PARTIAL ACETYL AND PARTIAL PROPIONYL ESTERS OF NATURAL CELLULOSE, IN WHICH FROM 1 TO 10% OF THE HYDROXYL GROUPS OF THE NATURAL CELLULOSE HAVE BEEN ESTERIFIED, IMPREGNATED WITH FROM ABOUT 6 TO 16% BY WEIGHT, BASED ON THE DRY MATERIAL, OF AN INSOLUBILIZED CONDENSATION PRODUCT SELECTED FROM THE GROUP CONSISTING OF UREA-FORMALDEHYDE, MELAMINE-FORMALDEHYDE, METHYLATED UREA-FORMALDEHYDE AND METHYLATED MELAMINE-FORMALDEHYDE CONDENSATION PRODUCTS AND MIXTURES THEREOF, SAID FIBERS BEING CHARACTERIZED BY A TENSILE STRENGTH WHICH IS SUBSTANTIALLY THE SAME AS THE UNTREATED NATURAL CELLULOSE TEXTILE FIBERS FROM WHICH THEY WERE PREPARED. 